docs: def _compute_mean(self, C, mag, dists, rake):
          """
          Compute and return mean value without site conditions,
          that is equations (1a) and (1b), p.2981-2982.
          """
          mean = (
              C['a1'] +
              self._compute_linear_magnitude_term(C, mag) +
              self._compute_quadratic_magnitude_term(C, mag) +
              self._compute_logarithmic_distance_term(C, mag, dists) +
              self._compute_faulting_style_term(C, rake)
          )
  
          return mean